1. Field of Technology
The present disclosure relates to multilayer overlays providing corrosion, erosion and/or abrasion resistance to surfaces of articles of manufacture. The present disclosure also relates to methods for applying multilayer overlays to article surfaces, wherein the overlays provide resistance to corrosion, erosion, and/or abrasion.
2. Description of the Background of the Technology
For many years, attempts have been made to reduce wear experienced by pipes, valves, gaskets, and other material flow parts in energy systems, refineries, coke plants, and chemical production facilities, as well as by components that handle or contact abrasive materials. Examples of such parts include pipe, valves, and other parts subjected to a flow of highly abrasive oil sands in energy production systems, or subjected to a flow of highly corrosive chemicals in chemical production plants. Other examples of such parts include excavating bucket teeth, grader blades, and hammers. The conditions promoting wear of such parts can be abrasive, erosive, and/or chemical in nature, and can be extremely aggressive. The nature of material flow parts, for example, often makes servicing and replacing them difficult, and the process downtime and man-hours associated with repairing or replacing parts in these systems can be very costly. Therefore, substantial efforts have been made to produce material flow parts for these applications that can better withstand the aggressive corrosive, erosive, and/or abrasive wear conditions to which the parts are subjected.
Materials including hard particles in a metallic matrix have been proposed for reducing the wear of surfaces of metallic parts. For example, Canadian patent application no. 2,498,073 describes a wear resistant material composed of boron carbide particles in a metal matrix, wherein the material is applied to the interior surface of a fluid conducting part. Also, Canadian patent application no. 1,018,474 describes a wear resistant material composed of conventional synthetic industrial diamond in an electroplated nickel matrix that is applied to a surface of a part to inhibit wear. The hard carbide and diamond particles in these prior art material provide wear resistance, and the matrix material provides toughness and allows the wear resistant particles to be securely associated with the surfaces to be protected from wear.
Diamond is the hardest and most chemically inert material known and has been used in some applications taking advantage of its substantial resistance to wear. Industrial diamond and tungsten carbide particles have been used in the superabrasives industry for many years. For example, combinations of tungsten carbide and conventional grit-size industrial diamond particles have been embedded in a metallic matrix such as cobalt or iron to provide materials for grinding wheels and saw blades. As is known in the art, “industrial diamond” refers to small diamond particles that are often synthetic, have no value as gemstones, and are used in the cutting tool, abrasives, construction, and other industries. The application of conventional industrial diamond to provide wear resistance has been extended to the fabrication of highly wear resistant parts composed of a polycrystalline diamond layer bonded to a tungsten carbide matrix material substrate.
Mined diamond has been available for industrial use since the early 1900's and became a material of strategic importance in the 1940's. Given the intrinsic value of diamond, efforts have been made for over 200 years to synthetically produce diamond. In 1797, Tennant demonstrated that diamond is a high density form of carbon, and it was postulated that subjecting common forms of carbon to pressure might produce diamond. Over 100 years ago, Hannay reported successfully producing diamond by sealing organic material and lithium into tubes and heating them to very high temperature. In the late 19th century, Moissan used the known solubility of carbon in solid iron to attempt diamond synthesis by quenching a high-temperature carbon/iron solution in water. The pressure generated by contraction of the iron on cooling was claimed to produce diamond. Although many additional attempts to produce diamond in the laboratory were made over the years, it is believed that until the 1950s those attempts were unsuccessful given the intrinsic difficulty of replicating the conditions under which diamond forms naturally. First, extremely high pressure is needed to achieve the compact, strongly bonded structure of diamond. Second, even when the extreme pressure necessary is achieved, very high temperature also is required so that the conversion to diamond occurs at a useful rate. Third, even when the pressure and temperature conditions are achieved, only very small diamond grains are produced. Achieving a large single crystal diamond requires meeting even further, more extensive conditions.
By 1941, the General Electric, Carborundum, and Norton companies and P. S. Bridgeman, a well known researcher in the field of high pressure, agreed to jointly investigate diamond synthesis, but the effort was discontinued prematurely due to the war. The parties did report some success in that they claimed to have subjected graphite at almost half a million psi to a temperature of 3000° C. for a few seconds through a thermite reaction. In 1951, General Electric formed a high pressure diamond group that came to include researchers H. A. Nerad, F. P. Bundy, H. M. Strong, H. T. Hall, R. H. Wentorf, J. E. Cheney, and H. P. Bovenkerk. On Dec. 16, 1954, Hall successfully obtained synthetic diamonds, and he duplicated his success in several runs over the next two weeks. During the succeeding few months, the GE group worked out the details of Hall's synthesis process. The first public announcement of success occurred in 1955, listing the names of Hall, Strong, and Wentorf. At the same time, both the DeBeers company and researchers in the USSR also reported the successful synthesis of diamond, although the initial U.S. patent on a process for producing synthetic diamond was awarded to General Electric.
Many additional processes for preparing synthetic diamond have been developed since the successes of General Electric and Hall. In certain of these processes, the nucleation and growth of diamond crystals is achieved under relatively low pressure and temperature conditions. The production of synthetic industrial diamond has now advanced to the point that the quantity of synthetic industrial diamond produced each year far exceeds the amount of mined industrial diamond. General Electric exited the commercial synthetic diamond business in 2003, when its superabrasives business was sold and began operations as Diamond Innovations. Diamond Innovations, Element Six, and Iljin Diamond, along with a number of smaller producers, make up the current primary players in the industrial diamond industry. The successful and large-scale production of synthetic diamond has made the material generally available at a cost justifying its use in industrial and other applications.
Given the hardness and wear resistance of industrial diamond and its present commercial availability, it would be advantageous to provide materials including industrial diamond that may be applied to surfaces of metallic parts to improve resistance to corrosion, erosion, and abrasion.